The Windows phone app which has gone free next as myAppFree app of the day for limited time is Lockscreener!.
By this app you can create collections of images that will update it periodically (about every 20 minutes because of a Windows Phone restriction) in the order that you prefer, also you apply filters to the lockscreen directly, without using other applications to save them first!
Lockscreener! Features:
Create themes and access quickly to the most recent ones, or add the most you use to the faves list.
Add images to the themes, delete the ones you no longer want or modify the order in which the lockscreen changes.
Enable random order or battery saver which paralyzes the lockscreen when your battery is low.
Slide down a picture to see how it would look if applied as lockscreen.
Use your voice: Say “Lockscreener” and the name of the theme you want as lockscreen to set it quickly.
Try our random filter and more!